A model of gel electrophoresis.

Electrophoretic migration of macromolecules through gels is described in terms of dislocation of the gel polymers by migrating molecules. The polymer displacement depends on two forces. The first is the electrokinetic force of the migrating macromolecules and the second is the resisting force of the polymers. The molecules migrate in discrete steps, and in each step they pass through one gel layer. "Doors" are formed by a dislocation of the polymer chains in one layer whereas "corridors" are formed by a deformation of the layer, accompanied by dislocation of the polymers in at least one layer above and below. The model is supported by experiments showing a loss of resolution in the gels comprising a branched, polymeric cross-linker, and a faster migration of a 23 kbp than a 9.4 kbp DNA fragment in two completely different matrices, including a novel cross-linked agarose gel.